1. Field of the Invention
This invention relates in general to a machine for making and applying a thin plastic covering to a rigid base article.
2. Description of the Prior Art
The prior art discloses two basic apparatuses for forming and applying a thin plastic covering to a rigid base article such that a subsequent thermoconstrictive process results in a tightly bonded plastic covering. U.S. Pat. No. 3,110,554, granted to K. Yazumi, discloses an apparatus for labeling packages. A thin plastic blank is processed into a tubular section using a heat sealing bar, for example. The diameter of the tubular section is only slightly larger than the diameter of the article to be covered. The section is then placed directly about the rigid body and a thermal operation contracts the plastic to make it adhere firmly to the surface of the rigid body.
U.S. Pat. No. 3,802,942, granted to S. W. Amberg et al., discloses another sleeve making apparatus. The thin plastic covering is supplied on a large web and cut into appropriately sized blanks. The plastic blanks are fed to a plastic sleeve forming means. The leading edge of the plastic blank is held to a cylindrical mandrel by the pressure differential created by the application of a vacuum through a plurality of vacuum ports formed in the mandrel and the external atmospheric pressure. The mandrel then rotates so as to wrap the plastic about the exterior surface of the mandrel. When a complete rotation is made, a heat sealing bar is supplied such that the ends of the plastic blank are sealed, forming a plastic sleeve. Then a preheated rigid base article is positioned above the mandrel such that their longitudinal axes coincide. A stripper sleeve, also longitudinally aligned but positioned below the mandrel, is raised upwardly until it engages the plastic sleeve and pushes it telescopically onto the rigid base article. The heat retained in the article causes the plastic sleeve to shrink slightly such that it remains in position relative to the article after the stripper sleeve is retracted. The article with its plastic covering is then subjected to the final thermoconstrictive process.